idnits 2.17.1 draft-cms-masque-connect-ip-00.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- -- The document has examples using IPv4 documentation addresses according to RFC6890, but does not use any IPv6 documentation addresses. Maybe there should be IPv6 examples, too? Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (12 April 2021) is 1108 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) ** Obsolete normative reference: RFC 7540 (ref. 'H2') (Obsoleted by RFC 9113) == Outdated reference: A later version (-11) exists of draft-ietf-masque-h3-datagram-00 ** Obsolete normative reference: RFC 7230 (Obsoleted by RFC 9110, RFC 9112) -- Obsolete informational reference (is this intentional?): RFC 7235 (ref. 'AUTH') (Obsoleted by RFC 9110) == Outdated reference: A later version (-03) exists of draft-ietf-masque-ip-proxy-reqs-01 Summary: 2 errors (**), 0 flaws (~~), 3 warnings (==), 3 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 MASQUE A. Chernyakhovsky 3 Internet-Draft D. McCall 4 Intended status: Standards Track D. Schinazi 5 Expires: 14 October 2021 Google LLC 6 12 April 2021 8 The CONNECT-IP HTTP Method 9 draft-cms-masque-connect-ip-00 11 Abstract 13 This document describes the CONNECT-IP HTTP method. CONNECT-IP is 14 similar to CONNECT-UDP, but allows transmitting IP packets, without 15 being limited to just TCP like CONNECT or UDP like CONNECT-UDP. 17 Discussion Venues 19 This note is to be removed before publishing as an RFC. 21 Discussion of this document takes place on the Multiplexed 22 Application Substrate over QUIC Encryption Working Group mailing list 23 (masque@ietf.org), which is archived at 24 https://mailarchive.ietf.org/arch/browse/masque/. 26 Source for this draft and an issue tracker can be found at 27 https://github.com/DavidSchinazi/draft-cms-masque-connect-ip. 29 Status of This Memo 31 This Internet-Draft is submitted in full conformance with the 32 provisions of BCP 78 and BCP 79. 34 Internet-Drafts are working documents of the Internet Engineering 35 Task Force (IETF). Note that other groups may also distribute 36 working documents as Internet-Drafts. The list of current Internet- 37 Drafts is at https://datatracker.ietf.org/drafts/current/. 39 Internet-Drafts are draft documents valid for a maximum of six months 40 and may be updated, replaced, or obsoleted by other documents at any 41 time. It is inappropriate to use Internet-Drafts as reference 42 material or to cite them other than as "work in progress." 44 This Internet-Draft will expire on 14 October 2021. 46 Copyright Notice 48 Copyright (c) 2021 IETF Trust and the persons identified as the 49 document authors. All rights reserved. 51 This document is subject to BCP 78 and the IETF Trust's Legal 52 Provisions Relating to IETF Documents (https://trustee.ietf.org/ 53 license-info) in effect on the date of publication of this document. 54 Please review these documents carefully, as they describe your rights 55 and restrictions with respect to this document. Code Components 56 extracted from this document must include Simplified BSD License text 57 as described in Section 4.e of the Trust Legal Provisions and are 58 provided without warranty as described in the Simplified BSD License. 60 Table of Contents 62 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 63 1.1. Conventions and Definitions . . . . . . . . . . . . . . . 3 64 2. The CONNECT-IP Method . . . . . . . . . . . . . . . . . . . . 3 65 3. Transmitting IP Packets using HTTP Datagrams . . . . . . . . 4 66 4. Routes . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 67 5. Stream Chunks . . . . . . . . . . . . . . . . . . . . . . . . 5 68 6. Messages . . . . . . . . . . . . . . . . . . . . . . . . . . 5 69 6.1. IP_PACKET Message . . . . . . . . . . . . . . . . . . . . 5 70 6.2. ADDRESS_ASSIGN Message . . . . . . . . . . . . . . . . . 6 71 6.3. ADDRESS_REQUEST Message . . . . . . . . . . . . . . . . . 6 72 6.4. ROUTE_ADVERTISEMENT Message . . . . . . . . . . . . . . . 7 73 6.5. ROUTE_REJECTION Message . . . . . . . . . . . . . . . . . 8 74 6.6. ROUTE_RESET Message . . . . . . . . . . . . . . . . . . . 8 75 6.7. SHUTDOWN Message . . . . . . . . . . . . . . . . . . . . 9 76 6.8. ATOMIC_START Message . . . . . . . . . . . . . . . . . . 9 77 6.9. ATOMIC_END Message . . . . . . . . . . . . . . . . . . . 10 78 7. Extensibility Considerations . . . . . . . . . . . . . . . . 10 79 8. Security Considerations . . . . . . . . . . . . . . . . . . . 10 80 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 81 9.1. HTTP Method . . . . . . . . . . . . . . . . . . . . . . . 11 82 9.2. Stream Chunk Type Registration . . . . . . . . . . . . . 11 83 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 11 84 10.1. Normative References . . . . . . . . . . . . . . . . . . 12 85 10.2. Informative References . . . . . . . . . . . . . . . . . 12 86 Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 13 87 A.1. Consumer VPN . . . . . . . . . . . . . . . . . . . . . . 13 88 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 13 89 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13 91 1. Introduction 93 This document describes the CONNECT-IP HTTP method. CONNECT-IP is 94 similar to CONNECT-UDP, but allows transmitting IP packets, without 95 being limited to just TCP like CONNECT or UDP like CONNECT-UDP. 97 CONNECT-IP allows endpoints to set up an IP tunnel between one 98 another. This can be used to implement a consumer VPN, point-to- 99 point, point-to-network, and network-to-network capabilities as 100 described in [REQS]. 102 1.1. Conventions and Definitions 104 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 105 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 106 "OPTIONAL" in this document are to be interpreted as described in BCP 107 14 [RFC2119] [RFC8174] when, and only when, they appear in all 108 capitals, as shown here. 110 In this document, we use the term "proxy" to refer to the HTTP server 111 that responds to the CONNECT-IP request. If there are HTTP 112 intermediaries (as defined in Section 2.3 of [RFC7230]) between the 113 client and the proxy, those are referred to as "intermediaries" in 114 this document. 116 2. The CONNECT-IP Method 118 The CONNECT-IP method establishes a stream to an endpoint server that 119 then permits the exchange of control data, such as IP address 120 information, reachable IP ranges, and other relevant information for 121 successfully transmitting IP datagrams between hosts. 123 The request-target of a CONNECT-IP request is a URI [URI] which uses 124 the "https" scheme and an immutable path of "/". When using HTTP/2 125 [H2] or later, CONNECT-IP requests use HTTP pseudo-headers with the 126 following requirements: 128 * The ":method" pseudo-header field is set to "CONNECT-IP". 130 * The ":scheme" pseudo-header field is set to "https". 132 * The ":path" pseudo-header field is set to "/". 134 * The ":authority" pseudo-header field contains the host and port of 135 the proxy. The target of a CONNECT-IP request is the server 136 providing the CONNECT-IP featureset, not an individual endpoint 137 with which a connection is desired. 139 A CONNECT-IP request that does not conform to these restrictions is 140 malformed (see [H2], Section 8.1.2.6). 142 Any 2xx (Successful) response indicates that the proxy is willing to 143 open an IP tunnel between it and the client. Any response other than 144 a successful response indicates that the tunnel has not yet been 145 formed. 147 A proxy MUST NOT send any Transfer-Encoding or Content-Length header 148 fields in a 2xx (Successful) response to CONNECT-IP. A client MUST 149 treat a successful response to CONNECT-IP containing any Content- 150 Length or Transfer-Encoding header fields as malformed. 152 A payload within a CONNECT-IP request message has no defined 153 semantics; a CONNECT-IP request with a non-empty payload is 154 malformed. Note that the CONNECT-IP stream is used to convey control 155 messages, but they are not semantically part of the request or 156 response themselves. 158 Responses to the CONNECT-IP method are not cacheable. 160 The lifetime of the tunnel is tied to the CONNECT-IP stream. Closing 161 the stream (via the FIN bit on a QUIC STREAM frame, or a QUIC 162 RESET_STREAM frame) closes the associated tunnel. 164 3. Transmitting IP Packets using HTTP Datagrams 166 When the HTTP connection supports HTTP/3 datagrams [H3DGRAM], IP 167 packets can be sent using them. The HTTP/3 Datagram Payload contains 168 a full IP packet, from the IP Version field until the last byte of 169 the IP Payload. 171 4. Routes 173 Endpoints have the ability to advertise and reject routes using the 174 ROUTE_ADVERTISEMENT (Section 6.4) and ROUTE_REJECTION (Section 6.4) 175 messages. Note that these messages are purely informational: receipt 176 of a ROUTE_ADVERTISEMENT message does not require the recipient to 177 start routing traffic to its peer. Additionally, if an endpoint 178 receives a ROUTE_REJECTION for a given prefix that it had previously 179 received a ROUTE_ADVERTISEMENT message for, then the two cancel out 180 and the endpoint MUST remove its state from the ROUTE_ADVERTISEMENT 181 message instead of installing new state for the ROUTE_REJECTION 182 message. Conversely, the same is true of a ROUTE_ADVERTISEMENT that 183 matches a previous ROUTE_REJECTION. Routes are handled via longest- 184 prefix-first preference, meaning that if a given IP prefix is covered 185 by multiple route advertisement and route rejections, the one with 186 the longest prefix is used. 188 5. Stream Chunks 190 The DATA stream tied to the bidirectional stream that the CONNECT-IP 191 request was sent on is a sequence of CONNECT-IP Stream Chunks, which 192 are defined as a sequence of type-length-value tuples using the 193 following format (using the notation from the "Notational 194 Conventions" section of [QUIC]): 196 CONNECT-IP Stream { 197 CONNECT-IP Stream Chunk (..) ..., 198 } 200 Figure 1: CONNECT-IP Stream Format 202 CONNECT-IP Stream Chunk { 203 CONNECT-IP Stream Chunk Type (i), 204 CONNECT-IP Stream Chunk Length (i), 205 CONNECT-IP Stream Chunk Value (..), 206 } 208 Figure 2: CONNECT-IP Stream Chunk Format 210 CONNECT-IP Stream Chunk Type: A variable-length integer indicating 211 the Type of the CONNECT-IP Stream Chunk. Endpoints that receive a 212 chunk with an unknown CONNECT-IP Stream Chunk Type MUST silently 213 skip over that chunk. 215 CONNECT-IP Stream Chunk Length: The length of the CONNECT-IP Stream 216 Chunk Value field following this field. Note that this field can 217 have a value of zero. 219 CONNECT-IP Stream Chunk Value: The payload of this chunk. Its 220 semantics are determined by the value of the CONNECT-IP Stream 221 Chunk Type field. 223 6. Messages 225 6.1. IP_PACKET Message 227 The IP_PACKET message allows conveying IP Packets when HTTP/3 228 Datagrams are not available. This message uses a CONNECT-IP Stream 229 Chunk Type of 0x00. Its value uses the following format: 231 IP_PACKET Message { 232 IP Packet (...), 233 } 235 Figure 3: IP_PACKET Message Format 237 IP Packet: A full IP packet, from the IP Version field until the 238 last byte of the IP Payload. 240 Note that this message MAY still be used even when HTTP/3 datagrams 241 are available. 243 6.2. ADDRESS_ASSIGN Message 245 The ADDRESS_ASSIGN message allows an endpoint to inform its peer that 246 it has assigned an IP address to it. It allows assigning a prefix 247 which can contain multiple addresses. This message uses a CONNECT-IP 248 Stream Chunk Type of 0x01. Its value uses the following format: 250 ADDRESS_ASSIGN Message { 251 IP Version (8), 252 IP Address (32..128), 253 IP Prefix Length (8), 254 } 256 Figure 4: ADDRESS_ASSIGN Message Format 258 IP Version: IP Version of this address assignment. MUST be either 4 259 or 6. 261 IP Address: Assigned IP address. If the IP Version field has value 262 4, the IP Address field SHALL have a length of 32 bits. If the IP 263 Version field has value 6, the IP Address field SHALL have a 264 length of 128 bits. 266 IP Prefix Length: Length of the IP Prefix assigned, in bits. MUST 267 be lesser or equal to the length of the IP Address field, in bits. 269 6.3. ADDRESS_REQUEST Message 271 The ADDRESS_REQUEST message allows an endpoint to request assignment 272 of an IP address from its peer. It allows the endpoint to optionally 273 indicate a preference for which address it would get assigned. This 274 message uses a CONNECT-IP Stream Chunk Type of 0x02. Its value uses 275 the following format: 277 ADDRESS_REQUEST Message { 278 IP Version (8), 279 IP Address (32..128), 280 IP Prefix Length (8), 281 } 283 Figure 5: ADDRESS_REQUEST Message Format 285 IP Version: IP Version of this address request. MUST be either 4 or 286 6. 288 IP Address: Requested IP address. If the IP Version field has value 289 4, the IP Address field SHALL have a length of 32 bits. If the IP 290 Version field has value 6, the IP Address field SHALL have a 291 length of 128 bits. 293 IP Prefix Length: Length of the IP Prefix requested, in bits. MUST 294 be lesser or equal to the length of the IP Address field, in bits. 296 Upon receiving the ADDRESS_REQUEST message, an endpoint SHOULD assign 297 an IP address to its peer, and then respond with an ADDRESS_ASSIGN 298 message to inform the peer of the assignment. 300 6.4. ROUTE_ADVERTISEMENT Message 302 The ROUTE_ADVERTISEMENT message allows an endpoint to communicate to 303 its peer that it is willing to route traffic to a given prefix. This 304 message uses a CONNECT-IP Stream Chunk Type of 0x03. Its value uses 305 the following format: 307 ROUTE_ADVERTISEMENT Message { 308 IP Version (8), 309 IP Address (32..128), 310 IP Prefix Length (8), 311 } 313 Figure 6: ROUTE_ADVERTISEMENT Message Format 315 IP Version: IP Version of this route advertisement. MUST be either 316 4 or 6. 318 IP Address: IP address of the advertised route. If the IP Version 319 field has value 4, the IP Address field SHALL have a length of 32 320 bits. If the IP Version field has value 6, the IP Address field 321 SHALL have a length of 128 bits. 323 IP Prefix Length: Length of the IP Prefix of the advertised route, 324 in bits. MUST be lesser or equal to the length of the IP Address 325 field, in bits. 327 Upon receiving the ROUTE_ADVERTISEMENT message, an endpoint MAY start 328 routing IP packets in that prefix to its peer. 330 6.5. ROUTE_REJECTION Message 332 The ROUTE_REJECTION message allows an endpoint to communicate to its 333 peer that it is not willing to route traffic to a given prefix. This 334 message uses a CONNECT-IP Stream Chunk Type of 0x04. Its value uses 335 the following format: 337 ROUTE_REJECTION Message { 338 IP Version (8), 339 IP Address (32..128), 340 IP Prefix Length (8), 341 } 343 Figure 7: ROUTE_REJECTION Message Format 345 IP Version: IP Version of this route rejection. MUST be either 4 or 346 6. 348 IP Address: IP address of the rejected route. If the IP Version 349 field has value 4, the IP Address field SHALL have a length of 32 350 bits. If the IP Version field has value 6, the IP Address field 351 SHALL have a length of 128 bits. 353 IP Prefix Length: Length of the IP Prefix of the advertised route, 354 in bits. MUST be lesser or equal to the length of the IP Address 355 field, in bits. 357 Upon receiving the ROUTE_REJECTION message, an endpoint MUST stop 358 routing IP packets in that prefix to its peer. Note that this 359 message can be reordered with DATAGRAM frames, and therefore an 360 endpoint that receives packets for routes it has rejected MUST NOT 361 treat that as an error. 363 6.6. ROUTE_RESET Message 365 The ROUTE_RESET message allows an endpoint to cancel any routes it 366 had previously advertised or denied. This message uses a CONNECT-IP 367 Stream Chunk Type of 0x05. Its value uses the following format: 369 ROUTE_RESET Message { 370 } 372 Figure 8: ROUTE_RESET Message Format 374 Upon receiving the ROUTE_RESET message, an endpoint MUST stop routing 375 IP packets to its peer. Note that this message can be reordered with 376 DATAGRAM frames, and therefore an endpoint that receives packets for 377 routes it has rejected MUST NOT treat that as an error. 379 The main purpose of the ROUTE_RESET message is to allow endpoints to 380 not have to remember the full list of routes they have shared with 381 their peer. In practice, it is expected that ROUTE_RESET messages 382 will be closely followed by ROUTE_ADVERTISEMENT messages that will 383 refill the routing table that was just cleared. 385 6.7. SHUTDOWN Message 387 The SHUTDOWN message allows an endpoint to communicate to its peer 388 that it is about to close the CONNECT-IP stream, with a string 389 explaining the reason for the shutdown. This message uses a CONNECT- 390 IP Stream Chunk Type of 0x06. Its value uses the following format: 392 SHUTDOWN Message { 393 Reason Phrase (..), 394 } 396 Figure 9: SHUTDOWN Message Format 398 Reason Phrase: Additional diagnostic information for the shutdown. 399 This SHOULD be a UTF-8 encoded string [UTF8], though the frame 400 does not carry information, such as language tags, that would aid 401 comprehension by any entity other than the one that created the 402 text. 404 Note that the SHUTDOWN message is informational, the tunnel is only 405 closed when its corresponding CONNECT-IP stream is closed. Endpoints 406 MAY close the tunnel with a reason phrase by sending the SHUTDOWN 407 message with the FIN bit set on the underlying QUIC STREAM frame that 408 carried it. 410 6.8. ATOMIC_START Message 412 The ATOMIC_START message allows an endpoint to create an atomic set 413 of messages. This message uses a CONNECT-IP Stream Chunk Type of 414 0x07. Its value uses the following format: 416 ATOMIC_START Message { 417 } 419 Figure 10: ATOMIC_START Message Format 421 Upon receiving an ATOMIC_START message, an endpoint MUST buffer all 422 incoming known messages until it receives an ATOMIC_END message. 423 Endpoints MUST NOT send two ATOMIC_START messages without an 424 ATOMIC_END message between them. 426 Endpoints MUST NOT buffer unknown messages. Endpoints MAY choose to 427 immediately process IP_PACKET and SHUTDOWN messages instead of 428 buffering them. Extensions that register new message types MAY 429 specify that it is allowed to skip buffering for them. 431 The purpose of this frame is to avoid timing issues where an endpoint 432 installs a route before an important route rejection was received. 433 Endpoints SHOULD group their initial configuration into an atomic 434 block to allow their peer to mark the tunnel as operational once the 435 whole block is parsed. 437 6.9. ATOMIC_END Message 439 The ATOMIC_END message allows an endpoint to end an atomic set of 440 messages. This message uses a CONNECT-IP Stream Chunk Type of 0x08. 441 Its value uses the following format: 443 ATOMIC_END Message { 444 } 446 Figure 11: ATOMIC_END Message Format 448 Upon receiving an ATOMIC_END message, an endpoint MUST parse all 449 previously buffered messages, in order of receipt. Endpoints MUST 450 NOT send an ATOMIC_END message without a preceding ATOMIC_START 451 message. 453 7. Extensibility Considerations 455 CONNECT-IP can be extended via multiple mechanisms to increase 456 functionality. There are two main ways to extend CONNECT-IP: HTTP 457 headers and CONNECT-IP Stream Chunk Types. For example, an 458 authentication extension could define an HTTP header that allows 459 endpoints to send authentication credentials to their peer during the 460 creation of the tunnel. Alternatively, one could specify an 461 extension that defines a new CONNECT-IP Stream Chunk Type which 462 allows exchanging DNS configuration between endpoints. 464 8. Security Considerations 466 There are significant risks in allowing arbitrary clients to 467 establish a tunnel to arbitrary servers, as that could allow bad 468 actors to send traffic and have it attributed to the proxy. Proxies 469 that support CONNECT-IP SHOULD restrict its use to authenticated 470 users. The HTTP Authorization header [AUTH] MAY be used to 471 authenticate clients. More complex authentication schemes are out of 472 scope for this document but can be implemented using CONNECT-IP 473 extensions. 475 9. IANA Considerations 477 9.1. HTTP Method 479 This document will request IANA to register "CONNECT-IP" in the HTTP 480 Method Registry (IETF review) maintained at 481 . 483 +-------------+------+------------+---------------+ 484 | Method Name | Safe | Idempotent | Reference | 485 +-------------+------+------------+---------------+ 486 | CONNECT-IP | no | no | This document | 487 +-------------+------+------------+---------------+ 489 9.2. Stream Chunk Type Registration 491 This document will request IANA to create a "CONNECT-IP Stream Chunk 492 Type" registry. This registry governs a 62-bit space, and follows 493 the registration policy for QUIC registries as defined in [QUIC]. In 494 addition to the fields required by the QUIC policy, registrations in 495 this registry MUST include the following fields: 497 Type: A short mnemonic for the type. 499 Description: A brief description of the type semantics, which MAY be 500 a summary if a specification reference is provided. 502 The initial contents of this registry are: 504 +-------+---------------------+---------------------+---------------+ 505 | Value | Type | Description | Reference | 506 +-------+---------------------+---------------------+---------------+ 507 | 0x00 | IP_PACKET | Full IP packet | This document | 508 | 0x01 | ADDRESS_ASSIGN | Address Assignment | This document | 509 | 0x02 | ADDRESS_REQUEST | Address Request | This document | 510 | 0x03 | ROUTE_ADVERTISEMENT | Route Advertisement | This document | 511 | 0x04 | ROUTE_REJECTION | Route Rejection | This document | 512 | 0x05 | ROUTE_RESET | Route Reset | This document | 513 | 0x06 | SHUTDOWN | Shutdown Reason | This document | 514 | 0x07 | ATOMIC_START | Atomic Start | This document | 515 | 0x08 | ATOMIC_END | Atomic End | This document | 516 +-------+---------------------+---------------------+---------------+ 518 Each value of the format "41 * N + 29" for integer values of N (that 519 is, 29, 70, 111, ...) are reserved; these values MUST NOT be assigned 520 by IANA and MUST NOT appear in the listing of assigned values. 522 10. References 523 10.1. Normative References 525 [H2] Belshe, M., Peon, R., and M. Thomson, Ed., "Hypertext 526 Transfer Protocol Version 2 (HTTP/2)", RFC 7540, 527 DOI 10.17487/RFC7540, May 2015, 528 . 530 [H3DGRAM] Schinazi, D. and L. Pardue, "Using QUIC Datagrams with 531 HTTP/3", Work in Progress, Internet-Draft, draft-ietf- 532 masque-h3-datagram-00, 29 January 2021, 533 . 536 [QUIC] Iyengar, J. and M. Thomson, "QUIC: A UDP-Based Multiplexed 537 and Secure Transport", Work in Progress, Internet-Draft, 538 draft-ietf-quic-transport-34, 14 January 2021, 539 . 542 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 543 Requirement Levels", BCP 14, RFC 2119, 544 DOI 10.17487/RFC2119, March 1997, 545 . 547 [RFC7230] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer 548 Protocol (HTTP/1.1): Message Syntax and Routing", 549 RFC 7230, DOI 10.17487/RFC7230, June 2014, 550 . 552 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 553 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 554 May 2017, . 556 [URI] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform 557 Resource Identifier (URI): Generic Syntax", STD 66, 558 RFC 3986, DOI 10.17487/RFC3986, January 2005, 559 . 561 [UTF8] Yergeau, F., "UTF-8, a transformation format of ISO 562 10646", STD 63, RFC 3629, DOI 10.17487/RFC3629, November 563 2003, . 565 10.2. Informative References 567 [AUTH] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer 568 Protocol (HTTP/1.1): Authentication", RFC 7235, 569 DOI 10.17487/RFC7235, June 2014, 570 . 572 [REQS] Chernyakhovsky, A., McCall, D., and D. Schinazi, 573 "Requirements for a MASQUE Protocol to Proxy IP Traffic", 574 Work in Progress, Internet-Draft, draft-ietf-masque-ip- 575 proxy-reqs-01, 8 January 2021, 576 . 579 Appendix A. Examples 581 A.1. Consumer VPN 583 In this scenario, the client will typically receive a single IP 584 address that the proxy has picked from a pool of addresses it 585 maintains. The client will route all traffic through the tunnel. 586 The exchange could look as follows: 588 Client Server 590 ADDRESS_REQUEST --------> 591 IP Version = 4 592 IP Address = 0.0.0.0 593 IP Prefix Length = 0 595 <-------- ADDRESS_ASSIGN 596 IP Version = 4 597 IP Address = 192.0.2.42 598 IP Prefix Length = 32 600 <-------- ROUTE_ADVERTISEMENT 601 IP Version = 4 602 IP Address = 0.0.0.0 603 IP Prefix Length = 0 605 Acknowledgments 607 The design of CONNECT-IP was inspired by discussions in the MASQUE 608 working group around [REQS]. The authors would like to thank 609 participants in those discussions for their feedback. 611 Authors' Addresses 613 Alex Chernyakhovsky 614 Google LLC 615 1600 Amphitheatre Parkway 616 Mountain View, California 94043, 617 United States of America 619 Email: achernya@google.com 620 Dallas McCall 621 Google LLC 622 1600 Amphitheatre Parkway 623 Mountain View, California 94043, 624 United States of America 626 Email: dallasmccall@google.com 628 David Schinazi 629 Google LLC 630 1600 Amphitheatre Parkway 631 Mountain View, California 94043, 632 United States of America 634 Email: dschinazi.ietf@gmail.com